This device relates to a distortion straightening method of a distortion straightening device to straighten distortion in long metal members.
Generally, during the process of cutting metallic members such as guide rails, having a relatively long longitudinally linear length, merely referred to as long members hereinafter, to a predetermined dimension, an oxide film remains on the surface of the long member if bending and other forms of distortion are not within the allowable values. Accordingly, it is necessary to measure the distortion to determine whether or not it is within the allowance before the cutting working of the long member, and to correct or remedy the distortion of the long member to be within the allowance by using a hydraulic press means, for example.
An automatic press-type straightening (i.e. strain correcting) apparatus for correcting the strain of a long metallic members is shown in FIG. 3 in perspective view. Referring to FIG. 3, the automatic straightening apparatus comprises a unit 1 for measuring the degree of straightness of the long member to be measured. A plurality of conveying rollers 3 are disposed at proper intervals on and along one side of a guide rail 2 for the straightness measuring unit 1 in a manner so that the rotation shafts of the rollers 3 are normal to the direction in which the guide rail 2 extends. Positioning rollers 5 for positioning the long member 4 at the measuring time thereof are arranged in the vicinity of the conveying rollers 3, respectively. A plurality of rotating rollers 6 are also arranged between the adjacent conveying rollers 3 on and along one side of the guide rail 2 to rotate the metallic long member by about 90.degree.. A distortion straightening station 7 provided with a portion for carrying out the pressing operation for the long metal member 4 is disposed at one end portion of the arrangement of the conveying rollers 3 and the rotating rollers 6. A plurality of other conveying rollers 8 are also disposed at proper intervals on the same side as those of the conveying rollers 3, with the distortion straightening station 7 interposed between the arrangements of the conveying rollers 3 and 8, and the conveying rollers 8 acting to subsequently convey the long metal member 4 pressed during the passing through the distortion straightening station 7. A plurality of rotating rollers 9 are also disposed between the adjacent conveying rollers 8 for rotating the long metal member 4 by about 90.degree..
The conveying rollers 3, the rotating rollers 6, the pressing portion of the distortion straightening station 7, the conveying rollers 8, and the rotating rollers 9 are arranged in alignment with each other for linearly conveying the long metal member 4 therealong in this order.
The long metal member 4 mounted on the conveying rollers 3 is conveyed to a predetermined position by rotation of the conveying rollers 3, and the long member 4 is positioned by the positioning rollers 5 at a portion at which the measuring of the member 4 is carried out. After the positioning of the long member 4 at the predetermined position, the straightness measuring unit 1 is moved on and along the guide rail 2 to thereby measure the strain of the long member 4 during the movement thereon. The measured data is input as electrical signals into a control board 10 located at a suitable portion in the vicinity of the distortion straightening apparatus.
After the completion of the measuring process of the measuring unit 1, the conveying rollers 3 are rotated to convey the long metal member 4 to the distortion straightening station 7. The long member 4 is subjected to the straightening of the distortion in response to electric signals from the control board 10 and the long member 4 for which the distortion has been straightened, and is then conveyed towards the conveying rollers 8. The long member 4, the strains of which have been once corrected, is conveyed back towards the distortion measuring unit 1 by the reverse rotations of the conveying rollers 3 and 8 to again measure the distortion in the long member 4. If distortion of the long member 4 is detected during this repeated measurement, the long member 4 is again conveyed by the rotation of the conveying rollers 3 and 8 to the distortion straightening station 7 to correct the strains in the manner described above. On the contrary, if no distortion is detected during the repeated measurement, the long member 4 is conveyed as it is by the rotation of the conveying rollers 3 and 8 and then conveyed out from the end arrangement of the conveying rollers 8.
A distortion straightening or straightening process to be carried out at the distortion straightening station 7 will be described hereunder with reference to FIGS. 4 to 7.
As illustrated in FIG. 4, one set of press heads 11a, 11b and 11c are disposed in the distortion straightening station 7 to be parallel to each other and the front ends thereof are directed to the same direction, and the other set of press heads 12a, 12b and 12c are also disposed at the distortion straightening station 7 to be parallel to each other and the front ends thereof directed in the same directions. These press heads 11a, 11b, 11c, and 12a, 12b, 12c are disposed in opposing arrangement in the order shown in FIG. 4 with the metallic long member 4 interposed therebetween. These press heads 11 and 12 are independently movable.
FIG. 5 illustrates the so-called "plus bending" operation. Referring to FIG. 5, the long metal member 4 is supported at two portions by the press heads 12a and 12c and the central portion between these supported portions of the long member 4 is as viewed downwardly, pressed by the press head 11b to carry out the straightening process for the long member 4. FIG. 6 illustrates the so-called "minus bending" operation. Referring to FIG. 6, the long metal member 4 is supported by one press head 12b and two portions on both sides of the press head 12b are downwardly pressed by the press heads 11a and 11c to carry out the straightening operation for the long member 4. FIG. 7 illustrates a bidirectional pressing operation in which FIG. 7, the long metal member 4 is pressed at three portions by the press heads 11a, 12b and 11c to carry out the straightening operation for the long member 4.
These straightening, i.e. distortion straightening, methods described above are conventionally known and carried out, and particularly, the plus bending method has been usually adopted as a highly desirable method.
One of the conventional straightening methods referred to above, i.e. the minus bending operation, by utilizing the automatic straightening apparatus of the type described hereinbefore will be now described in detail with reference to FIG. 8.
The amounts s of the distortions of a metallic long member 4 are subsequently measured for each preset correction span value 1 and the measured data is input to the control board as electrical signals. When the measured distortion amount s of a certain portion of the long member 4 exceeds the predetermined reference value, the portion is determined as a portion to undergo distortion straightening and the measured distortion amount s at that portion is determined as the amount of straightening. The strain of the metallic long member 4 is then strain-corrected in the strain correcting station 7 in accordance with the data input into the control board 10.
However, with the straightening method described above, the value of the distortion of the long member for every correction span is regarded as the amount of distortion to be corrected. According to this method, the distortion may be partially corrected at respective portions of the long member to be measured, but not totally throughout the whole length thereof. In a certain case, the long member may not be totally corrected to be straight throughout the whole length thereof. In another case wherein the long member to be straightened has a totally smooth and gentle distortion, i.e. a curve, the portions to have their distortion straightened may not be detected as distortion straightening portions by the use of the conventional method of detecting the portions to be corrected.